java - Swing——根据单元格的值设置单元格的颜色

Question

我想根据单元格的值设置单元格的颜色。在谷歌上搜索了一下，我发现我可以使用这样的方法来做到这一点:

public class TableCellRenderer extends DefaultTableCellRenderer {

    @Override
    public Component getTableCellRendererComponent(
       JTable table, Object value, 
       boolean isSelected, boolean hasFocus, 
       int row, int col)  
    {
       // get the DefaultCellRenderer to give you the basic component
       Component c = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, col);
       // apply your rules
       if (value.toString().equals("Red"))
          c.setBackground(Color.RED);
       else  
          c.setBackground(Color.GRAY);
       return c;
    }
 }

但我遇到的问题是，我想修改的代码已经为 JTable 的列设置了 TableCellRendererer。代码中有一个函数如下所示:

private void configureTableColumns() {      
        Enumeration columns = this.table.getColumnModel().getColumns();

        while (columns.hasMoreElements()) {
            TableColumn tableColumn = (TableColumn) columns.nextElement();

            this.setCellRenderer(tableColumn);
            TableCellRenderer renderer = tableColumn.getCellRenderer();

            if (renderer == null) {
                renderer = this.table.getDefaultRenderer(Object.class);
            }
            tableColumn.setCellRenderer(renderer);
            this.setCellEditor(tableColumn);
        }
    }

使用上面的代码，我还需要添加前面显示的 TableCellRenderer 类吗？我想要做的就是检查单元格的值是否为“ABC”并将背景设置为红色。

更新:

我确实尝试将我的 TableCellRenderer 版本添加为我要修改的代码中的内部类，但我收到一个错误，指出 tableColumn.getCellRenderer() 中存在类型不匹配。

Type mismatch: cannot convert from TableCellRenderer to MyTableExample.TableCellRenderer

谢谢

Answer 1

重写 prepareRenderer 方法。

例子:

public Component prepareRenderer (TableCellRenderer renderer, int rowIndex, int columnIndex){  
Component componenet = super.prepareRenderer(renderer, rowIndex, columnIndex);  

if(getValueAt(rowIndex, columnIndex).toString().equals("Red")) {  
   componenet.setBackground(Color.RED);  
} else if(getValueAt(rowIndex, columnIndex).toString().equals("Green")) {
   componenet.setBackground(Color.GREEN);
}
return componenet;
} 

更新:

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableCellRenderer;


public class PrepareRendereEx {

public static void main(String[] args) {

    JFrame frame = new JFrame();
    frame.setSize(new Dimension(400, 100));

    Object data[][] = { {"java", "j2ee"}, 
                        {"java", "j2ee"}, 
                        {"java", "j2ee"}
                      };
    Object[] columnNames = {"Java", "J2EE"};

    DefaultTableModel model = new DefaultTableModel(data, columnNames);
    JTable table = new JTable(model) {
        @Override
        public Component prepareRenderer(TableCellRenderer renderer, int rowIndex,
                int columnIndex) {
            JComponent component = (JComponent) super.prepareRenderer(renderer, rowIndex, columnIndex);  

            if(getValueAt(rowIndex, 0).toString().equalsIgnoreCase("java") && columnIndex == 0) {
                component.setBackground(Color.RED);
            } else if(getValueAt(rowIndex, 1).toString().equalsIgnoreCase("j2ee") && columnIndex == 1){
                component.setBackground(Color.GREEN);
            }

            return component;
        }
    };

    frame.add(new JScrollPane(table));
    frame.setVisible(true);
}
}

输出: